Introduction

Emit Vision gives your team a single SDK to capture errors, user events, feature flag evaluations, and session data — all in a self-hosted platform you control. No third-party analytics vendor stores your users' data.

What you can track

Capability	What it does
Error tracking	Captures unhandled exceptions and promise rejections automatically, plus manual `captureError()` calls with full context
Analytics events	`captureEvent()` records product actions — signups, button clicks, checkout steps — with typed properties and tags
Feature flags	`evaluateFlags()` evaluates flags server-side and logs exposures so you can analyze flag impact alongside other events
Sessions	Groups events from a single browser or worker session into a timeline you can replay and filter

Choosing the right SDK

Pick the package that matches where you're running code:

Your environment	Package
Vanilla JS, Svelte, Vue, any browser app	`@emit-vision/sdk-js`
React (CRA, Vite, non-Next.js)	`@emit-vision/sdk-react`
Next.js App Router	`@emit-vision/sdk-next`
Node.js servers and background workers	`@emit-vision/sdk-node`

You can use multiple packages in the same project. A Next.js app that also runs a Node.js job queue would use @emit-vision/sdk-next in the web layer and @emit-vision/sdk-node in the worker.

The React and Next.js packages are thin wrappers around sdk-js. They share the same ingest contract, so events, errors, and sessions from all packages appear in the same dashboard views.

How data flows

Your app  →  SDK (batch + queue)  →  POST /v1/ingest  →  API  →  Storage
                                                                      ↓
                                                             Dashboard queries

The SDK batches events in memory and flushes them on an interval (default 5 s) or when the batch reaches a size threshold (default 20 items). You can call flush() manually before navigation or shutdown.

Let an agent get you set up. If you use Claude Code, the init-emit-sdk skill detects your framework, installs the right package, and wires up the boilerplate automatically. See AI-Assisted Setup for instructions.

Ready to send your first event? Jump to Quick Start — you'll have data in the dashboard in under 10 minutes.

Next steps

Quick Start — first event in under 10 minutes
Installation — full setup guide for each SDK
Core Concepts — how sessions, events, errors, and releases relate